A reevaluation of predatory orbiliaceous fungi. I. Phylogenetic analysis using rDNA sequence data

A 1.2 kb long fragment of ribosomal DNA, including the 3' half of the 18S r DNA, the ITS1 region, the 5.8S rDNA, and the ITS2 region was sequenced in 2 0 strains of predatory hyphomycetes and allied species. Additional sequence s were obtained from GenBank and a conspectus of the evolution of the preda tory orbiliaceous fungi is provided. Amongst the species studied so far, no secondary loss of predacity could be detected. The predatory taxa were fou nd to have evolved from within the genus Orbilia. Two major monophyletic cl ades were identified: species possessing constricting rings (group I), and species with various adhesive trapping devices. The latter clade could be s ubdivided into at least three monophyletic groups, corresponding to species with adhesive networks (group II), adhesive columns or unstalked adhesive knobs (group III), and stalked adhesive knobs (group IV). Species with non- constricting rings appeared as a terminal development within group IV. The species possessing constricting rings (group I) had a basal position relati ve to species with adhesive trapping devices, but this relationship had no significant bootstrap support.